The present disclosure relates to audio applications, and more specifically, to audio amplifier circuits.
Conventional audio amplifiers typically require switchable microphone lines that provide low current DC output or are highly expensive. In digital audio systems, for example, headphone output lines typically require a digital to analog converter (DAC) to convert the digital output signal into an analog audio signal that can be output from the headphones. The DAC typically requires a low pass filter circuit to filter out of audio-band high frequency noise. To achieve the audio-band high frequency noise filtering process, conventional systems employ a separate low pass filter stage, followed by a second separate headphone amplifier stage.